Dairy products

The ketone 2 heptanone has been identified as contnbuting to the odor of a number of dairy products including condensed milk and cheddar cheese Describe a synthesis of 2 heptanone from acetylene and any necessary organic or inorganic reagents... 

The saturated fatty acids, stearic [57-11-4] and palmitic [57-10-3], are found in animal fats and dairy products. Extensive studies point to the deleterious effect of these acids on arterial walls as a result it is recommended that saturated fatty acid intake be carefully controlled and intake limited (23). 

A good compilation of the functions of fats in various food products is available (26). Some functions are quite subtle, eg, fats lend sheen, color, color development, and crystallinity. One of the principal roles is that of texture modification which includes viscosity, tenderness (shortening), control of ice crystals, elasticity, and flakiness, as in puff pastry. Fats also contribute to moisture retention, flavor in cultured dairy products, and heat transfer in deep fried foods. For the new technology of microwave cooking, fats assist in the distribution of the heating patterns of microwave cooking. 

The most difficult property of fat to replace is flavor. Great expenditure of effort has gone into producing a tme butter flavor as flavor boosters in nondairy fat products and in dairy products including milk, cream, butter, and ice cream. Results have led to a successful dupHcation of buttery flavors which closely match the intended target. 

There is more activity in dairy products than anywhere else in the food industry. Ice milk and fro2en yogurt, early leaders in the field, rose rapidly in sales then plummeted. Fat-free ice cream has been marketed, but final results are not yet available. Sales of these products have not cannibalized traditional ice cream (35). Standards for traditional ice cream call for a minimum of 10% butterfat. One fat-free ice cream product is prepared from nonfat milk (skim) and cellulose gum. Fat-free ice creams have encountered strong resistance in some segments of the retail trade. Retailers in Maine and New York, states with important dairy producing industries, refuse to sell such products (36). 

One frozen dessert is made with Simplesse, a protein-based fat mimetic that contains no fat (37). Other dairy product developments include a fat flavor, produced by encapsulating milk fatty acids in maltodextrins (38) fat-free cottage cheeses and 2% fat milk, prepared by steam stripping cream with partial fat addback, with a cholesterol level about 60% lower than the starting material (39). 

Sorhita.n nd Sorbitol Esters. This group of emulsifiers is formed from the reaction of sorbitan and stearic acid. Sorbitan monostearate is often used in combination with polysorbate in ice cream, imitation dairy products, and baking appHcations (36). 

Sucrose Esters. These newer emulsifiers, approved for direct addition in the United States in 1983 (35), ate formed when sucrose is combined with various fatty acids and the resulting emulsion is dehydrated. These additives are odorless and tasteless, and can withstand the retort process. They are used in products when standards of identity do not preclude their use, such as baked goods, baking mixes, dairy product analogues, fto2en dairy desserts and mixes, and whipped milk products (39). High price has limited use in the United States, but these compounds ate used extensively in Japan as emulsifiers in baked goods (40). 

Fa.tMimetics. Existing fat mimetics are either carbohydrate-, ceUulosic (fiber)-, protein-, or gum-based. These are used in a wide variety of appHcations including baked goods, salad dressings, frozen desserts, meats, confections, and dairy products. Table 3 Hsts some of the commercially available fat mimetics. 

Acesulfame K. Acesulfame K [55589-62-3] C H NO S -K, is an oxathia2iae derivative approximately 200 times as sweet as sucrose at a 3% concentration ia solutioa (70). It is approved for use as a nonnutritive sweeteaer ia 25 couatties (71), and ia the United States has approval for use in chewing gum, confectionery products, dry mixes for beverages, puddings, gelatins, and dairy product analogues, and as a tabletop sweetener (72). 

Sorbates. The sodium and potassium salts of sorbic acid [110-44-1], ate used as mold and yeast inhibitors in dairy products, chemically... 

Gum Arabic. Gum arabic [9000-01-5] is an exudate of the Acacia tree, found in the Middle East. It dissolves readily in water to produce low viscosity solutions. It is used in confectionery products, bakery toppings, beverages, fro2en dairy products, and dry drink mixes (86). 

Cellulose. The principal stmctural component of plant ceU waUs is ceUulose (qv). The most widely used ceUulose derivative is the sodium salt of carboxymethylceUulose (CMC). It is made by treating ceUulose with sodium hydroxide—chloroacetic acid. CMC is widely used in the food industry in products such as baked goods, icings, symps, gla2es, fro2en dairy products, and dry drink mixes (89). 

MCC is used as a stabili2er in fro2en desserts, meats, dairy products, baked goods, and aerosol toppings (91). 

Conventional thermoforming of polystyrene and PVC is the most widely used technique for making packages for dairy products and for disposable cups and trays. 

Lactic acid-producing bacteria associated with fermented dairy products have been found to produce antibiotic-like compounds caUed bacteriocins. Concentrations of these natural antibiotics can be added to refrigerated foods in the form of an extract of the fermentation process to help prevent microbial spoilage. Other natural antibiotics are produced by Penicillium wqueforti the mold associated with Roquefort and blue cheese, and by Propionibacterium sp., which produce propionic acid and are associated with Swiss-type cheeses (3). 

Cells of microorganisms have constituted a portion of human food siace ancient times. Yeast-leavened baked products contain the residual nutrients from the yeast cells destroyed duriag bakiag (see Bakery processes and leavening agents). Cultured dairy products, such as yogurt, buttermilk, and sour cream, contain up to lO cells of lactic acid bacteria per gram (19) (see Milk and milkproducts). Other examples of fermented foods consumed siace early times iaclude fermented meats, fish, and soybean products. 

Fat Content of Milk. Raw milk as well as many dairy products are routinely analyzed for their fat content. The Babcock test, or one of its modifications, has been a standard direct measure for many years and is being replaced by indirect means, particularly for production operations. The Babcock test employs a bottle with an extended and caHbrated neck, milk plus sulfuric acid [7664-93-9] to digest the protein, and a centrifuge to concentrate the fat into the caHbrated neck. The percentage of fat in the milk is read direcflv from the neck of the bottle with a divider or caHper, rea ding to... 

Dried buttermilk is made by either the dmm or spray process. Buttermilk is usually pasteurized before drying, even though the milk was previously pasteurized before churning. Dried buttermilk is used primarily for baking, confectionery, and dairy products. 

R. T. MarshaU, ed.. Standard Methodsfor the Examination of Dairy Products, 16th ed., American PubUc Health Association, Washington, D.C., 1993, 546 pp. 

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